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Topic

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Left common carotid artery

The left common carotid artery (CCA) is a major artery of the neck and head that originates directly from the aortic arch, between the brachiocephalic trunk (to its right) and the left subclavian artery (to its left). It ascends vertically within the superior mediastinum and neck, enclosed by the carotid sheath, alongside the internal jugular vein and vagus nerve (CN X).

The left CCA is usually longer than the right because it arises directly from the aortic arch instead of the brachiocephalic trunk. It ascends until the level of the upper border of the thyroid cartilage (C3–C4 vertebral level), where it bifurcates into the internal carotid artery (ICA) and external carotid artery (ECA). These branches are critical for supplying the brain, face, scalp, neck, and pharyngeal/laryngeal structures.

The left CCA is of great clinical importance due to its role in cerebral perfusion, its involvement in atherosclerosis, stenosis, and stroke, and its accessibility for carotid endarterectomy, stenting, and imaging.

Synonyms

  • Left CCA

  • Arteria carotis communis sinistra

  • Left carotid artery

Function

  • Provides major arterial blood supply to the head and neck

  • Delivers oxygenated blood to the brain (via the ICA) and face/scalp (via the ECA)

  • Maintains cerebral perfusion through direct communication with the Circle of Willis

  • Serves as a landmark and access point for diagnostic and interventional vascular procedures

Branches

  • No branches in the neck (typically) until bifurcation

  • At C3–C4 level, bifurcates into:

    • Internal carotid artery (ICA): supplies brain and eyes

    • External carotid artery (ECA): supplies face, scalp, neck, pharynx, larynx, thyroid

MRI Appearance

T1-weighted images:

  • Blood flow appears as a signal void (black lumen) in non-contrast imaging

  • Vessel wall shows low signal rim; surrounding neck fat is hyperintense, aiding identification

T2-weighted images:

  • Lumen shows signal void due to flow

  • Perivascular pathology (e.g., edema, tumor invasion) appears as hyperintensity adjacent to the artery

STIR (Short Tau Inversion Recovery):

  • Suppresses fat signal, improving visualization of arterial margins

  • Wall abnormalities, edema, or inflammatory changes appear hyperintense

  • Useful for detecting arteritis or soft tissue extension

T1 Post-Contrast (Gadolinium-enhanced):

  • Lumen enhances brightly and homogeneously

  • Clearly delineates carotid bifurcation, stenosis, plaque, dissection, or aneurysm

  • Essential for MR angiography (MRA) of the neck and cerebral vessels

CT Appearance

Non-contrast CT:

  • Appears as a tubular soft tissue density in the carotid sheath

  • Calcified atherosclerotic plaques are seen as hyperdense foci along the wall

CT Angiography (CTA):

  • Provides high-resolution visualization of origin, course, bifurcation, and pathology

  • Detects atherosclerotic stenosis, thrombosis, aneurysm, dissection, or occlusion

  • Axial and multiplanar reconstructions allow precise surgical and interventional planning

MRI image

Left common carotid artery MRI coronal image -img-00000-00000

CT image

Left common carotid arteryCT axial image -img-00000-00000